1. Technical Field
The present disclosure relates to a charger and an electrophotographic image forming apparatus such as copier, facsimile machine, and scanner, in particular, using the charger.
2. Description of the Related Art
As a useful charger for charging a surface of photoreceptor in image forming apparatus, corona charger employing corona discharge is known. In corona charger, a wire is serving as a discharge electrode. As the wire is contaminated with powder dust such as toner or corona discharge products, the discharge electrode gets less able to uniformly discharge. The resulting image may be accompanied by black or white strip-like or band-like abnormal image and/or image density unevenness. The life-span of the charger is constrained by the degree of wire contamination, and therefore an effective method for removing foreign substances from the wire is demanded. In attempting to solve this problem, the use of a wire cleaner which is composed of felt pad, brush, abrasive-containing non-woven fabric, glass-containing resin, etc., has been proposed. As another approach, a gold-plated wire has been proposed for the purpose of facilitating the removal of foreign substances from the wire.
Glass-containing resin is said to have the best cleaning ability among various materials used for wire cleaners. However, glass-containing resin will scrape off not only foreign substances but also gold plating. A portion of the wire where the gold plating has been scraped off will deteriorate in discharging function and will cause black strip-like or band-like abnormal image. Accordingly, glass-containing resin can be improved in cleaning ability to the extent that gold plating will not be scraped off, which may be insufficient in terms of cleaning ability.